Home Forums Reloading Varmint Rifles Rocky, how are you measuring case............?

Are you measuring new, FL sized, once-fired factory brass.

Measuring web, length, and col length after FL sizing (-.001 shoulder datum for chamber, shoulder movement before next sizing (will be 5th firing of "prepped" brass) and after next sizing for brass I'm using for Blue Dot. Everything right on plus or minus .001, and went to 12.9 grains of Blue Dot last shoot, measuring before shoot and after. Kind of surprised me on the 12.9 charge versus 6 gr. charge.

No flattening of primers, (only one discernable with strong light, at angle to cartridge, was first round out of clean barrel AND chamber, perhaps a bit of lube remaining in chamber, and very minute compared to all other fired cartridges. 12.9 charged cases measured same as the single digit charges of Blue Dot.

Next test with the 1/2 inch load, for velocity, trajectory, and wind drift, if weather cooperates wind-wise.

So far it's PPP (Puddin' Percolating Properly)! Much less muzzle blast with Blue Dot as compared to 4198 in the 20 inch barrel. Kind of anal approach, but if problem, gives me better chance to learn why and where with my meaurements.

Well, our friend denton has convinced me that measuring case expansion is a waste of time - and proves nothing besides. He's a whiz with statistics and such, so I can't argue. Plus, he turned me on to what DOES work: the Pressure Trace system that measures chamber pressures electronically. An eye-opener believe me.

I still haven't gotten a strain gauge glued to my .221 Fireball for specific tests on Blue Dot pressure curves, but I will do so as soon as I can wedge that project in.

I kind of agree with the pressure measuring, did it some, and too much variation involved to measure.

I'm trying to measure for any noticeable change actually in brass I KNOW from previous firings. Will look for this on velocity check. I'll be waiting for the Blue Dot data on the pressure trace. Hope to size to night, to see if any case stretch on the higher Blue Dot loads. Will compare shoulder datum before sizing also. Off this thing, lightening is here.